Mechanized multi-instrument surgical system

ABSTRACT

A surgical system includes an instrument driver having a distal end positionable in a body cavity and a user input device. The instrument driver and user input device are positioned to removably receive distal and proximal portions, respectively, of a surgical instrument. The user input device is configured to generate movement signals in response to manual manipulation of the proximal portion of the surgical instrument. At least one motor operable to actuate the instrument driver in response to the movement signals and to thereby change position of the distal portion of the surgical instrument within the body cavity.

This application is a continuation of U.S. Ser. No. 13/759,036, filedFeb. 4, 2013, which claims priority to U.S. Provisional Application No.61/594,362, filed Feb. 2, 2012, and U.S. Provisional Application No.61/714,737, filed Oct. 16, 2012. Each of the foregoing is incorporatedherein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of access devices and portsthrough which flexible medical instruments may be introduced into a bodycavity and steered or deflected.

BACKGROUND

In conventional laparoscopic procedures, multiple small incisions areformed through the skin, underlying muscle and peritoneal tissue toprovide access to the peritoneal cavity for the various medicalinstruments and scopes needed to complete the procedure. The peritonealcavity is typically inflated using insufflation gas to expand thecavity, thus improving visualization and working space. In a typicallaparoscopic medical procedure, four ports are strategically placedaround the abdominal area allowing the surgeon visualization and use ofinstruments using principles of triangulation to approach the surgicaltarget. While this procedure is very effective and has stood as the goldstandard for minimally invasive surgery, it suffers from a number ofdrawbacks. One such drawback is the need for multiple incisions to placethe four ports, which increases the risk of complications such aspost-operative herniation and prolonged patient recovery. The four portmethod also raises concerns of cosmesis, leaving the patient with fourabdominal scars.

Further developments have led to systems allowing procedures to beperformed using multiple instruments passed through a single incision orport. In some such single port procedures, visualization andtriangulation are compromised due to linear instrumentationmanipulation, and spatial confinement resulting in what has been knownas “sword fighting” between instruments.

Improvements on the prior single port techniques are found in themulti-instrument access devices suitable for use in SPS procedures andother laparoscopic procedures and described in co-pending U.S.application Ser. No. 11/804,063 ('063 application) filed May 17, 2007and entitled SYSTEM AND METHOD FOR MULTI-INSTRUMENT SURGICAL ACCESSUSING A SINGLE ACCESS PORT, U.S. application Ser. No. 12/209,408 filedSep. 12, 2008 and entitled MULTI-INSTRUMENT ACCESS DEVICES AND SYSTEMS,U.S. application Ser. No. 12/511,043, filed Jul. 28, 2009, entitledMULTI-INSTRUMENT ACCESS DEVICES AND SYSTEMS, and U.S. application Ser.No. 12/649,307, filed Dec. 29, 2009, (US Publication 2011/0230723)entitled ACTIVE INSTRUMENT PORT SYSTEM FOR MINIMALLY-INVASIVE SURGICALPROCEDURES, each of which is incorporated herein by reference.

U.S. application Ser. No. 12/649,307 (US Publication 2011/0230723) filedDec. 29, 2009 and entitled ACTIVE INSTRUMENT PORT FOR MINIMALLY-INVASIVESURGICAL PROCEDURES describes a system for use in performing multi-toolminimally invasive medical procedures using a plurality of instrumentspassed through a single incision in a body cavity. The disclosed systemincludes an insertion tube and a pair of instrument delivery tubes(IDTs) extending from the distal end of the insertion tube. Each IDT hassteerable distal portion positioned distal to the distal end of theinsertion tube. In use, flexible instruments passed through the IDTs aresteered by actively deflecting the deflectable distal portions of theIDTs. In particular, proximal actuators (shown as ball-and-socket orgimbal type actuators) for the IDTs are positioned proximally of theinsertion tube. Instruments to be deployed from the IDTs into the bodycavity are inserted through the proximal actuators into the IDTs. Theproximal actuators are moveable in response to manipulation of thehandles of instruments extending through the IDTs. Movement of theproximal actuators engages pull elements (e.g. wires, cables etc) thatextend from the proximal actuators to the deflectable sections of theIDT's, thus steering the distal portions of the IDTs (and thus thedistal ends of the instruments themselves). Additional instruments suchas scopes and other instruments may also be passed through the insertiontube (such as through rigid instrument channels) and used simultaneouslywith the instruments deployed through the IDTs.

Additional examples of proximal actuators and/or IDT shafts that may beused in such access systems are described in U.S. 2011/0184231, entitledDEFLECTABLE INSTRUMENT PORTS, U.S. 2011/0060183, entitledMULTI-INSTRUMENT ACCESS DEVICES AND SYSTEMS, and U.S. 2011/0251599entitled DEFLECTABLE INSTRUMENT SHAFTS, each of which is incorporatedherein by reference.

The present application describes new multi-instrument surgical accesssystems for use in minimally invasive procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a motor-assisted multi-instrumentsurgical system. FIGS. 1B through 18 are various views of components ofthe first embodiment, in which:

FIG. 1B shows the system supported by an arm and positioned relative toan operating table.

FIG. 1C is a partially exploded perspective view of the base unit, rolldriver and finger drive assembly.

FIG. 1D is a perspective view of a proximal part of the finger driveassembly.

FIG. 2A is a perspective view of the distal portion of the deploymentmechanism.

FIG. 2B is a perspective view of the proximal portion of the deploymentmechanism.

FIG. 2C is a plan view of the underside of the proximal portion of thedeployment mechanism.

FIG. 3 is a perspective view of a finger driver, including the pulleyhousing.

FIG. 4A is similar to FIG. 3, but without the pulley housing.

FIG. 4B is a bottom perspective view of the components of the fingerdriver, without the pulley housing, proximal tube and cables.

FIG. 5A shows a pulley of a finger driver.

FIGS. 5B and 5C are partially exploded views of the pulley of FIG. 5A.

FIGS. 6A and 6B schematically illustrate operation of the pulleys of thefinger driver.

FIG. 7A is a perspective view showing the underside of the finger driveassembly.

FIG. 7B is a perspective view showing the top side of the base unit.

FIG. 8A is a plan view showing the layout of the motors, sensors andgear assemblies within one half of the base unit.

FIG. 8B is a perspective view of one of the motors and gear assembliesfrom FIG. 8A.

FIG. 9 is a perspective view of a roll driver.

FIG. 10 is a perspective view of the roll drive tube and gear assemblyof the roll driver.

FIG. 11A is a side elevation view of an instrument that may be used withthe system.

FIG. 11B is a perspective view of the handle and proximal shaft of theFIG. 11A instrument.

FIG. 12A is a perspective view of the drive segment of the instrument ofFIG. 11A.

FIG. 12B shows the drive segment of FIG. 12A positioned within the rolldrive tube.

FIGS. 13A and 13B are end views of an alternative roll drive tube anddrive segment, respective.

FIG. 13C shows rotational engagement of the roll drive tube and drivesegment of FIGS. 13A and 13B.

FIG. 14 shows rotational engagement of a second alternative roll drivetube and drive segment.

FIG. 15 is an exploded view of a tubular connector positionable betweenthe housing and roll driver of FIG. 1A.

FIG. 16 is a perspective view of the command interface, showing theinstrument box separated from the brackets. The handle of an instrument,but not its distal shaft, is shown.

FIG. 17A is a proximal perspective view of the instrument box with thehousing removed and with an instrument handle withdrawn from theoperative position. The distal shaft of the instrument is not shown.

FIG. 17B is a distal perspective view of the instrument box with thehousing removed.

FIG. 18A is a block diagram schematically illustrating components of avariation of the system;

FIG. 18B schematically illustrates an exemplary algorithm forcontrolling movement of the fingers by the system.

FIG. 19 is a perspective view of a second embodiment.

FIG. 20 is a perspective view of a third embodiment.

FIG. 21 is a perspective view of a fourth embodiment.

FIG. 22 is a perspective view of a fifth embodiment.

FIG. 23 is a perspective view of a sixth embodiment.

FIG. 24 is a perspective view of a seventh embodiment.

FIG. 25 is a perspective view of a user interface that may be part ofthe sixth and seventh embodiments.

FIG. 26 is a perspective view of an eighth embodiment.

DETAILED DESCRIPTION

The present application discloses a new motor-assisted multi-instrumentsurgical system having certain advantages over prior art systems.

Overview

Referring to FIG. 1, a first embodiment of a surgical access system 2includes a finger drive assembly 200 comprising a housing 210 and aninsertion cannula 212 extending distally from the housing 210. Steerableinstrument delivery tubes or tubular fingers 214 extend distally fromthe insertion cannula 212. The tubular fingers 214 have lumen forreceiving passively flexible surgical instruments 100. As will bedescribed below, motor-driven finger drivers within the finger driveassembly 200 steer the fingers 214 using cables anchored at the distalends of the fingers. Associated with each tubular finger 214 is acorresponding motor driven roll driver 216—which acts on a distalportion of the instrument shaft to rotate it axially.

In the first embodiment, the motors used to actuate the finger driversand the roll drivers, as well as associated controllers and electronicsare housed within a base unit 218, and the finger drive assembly 200 andthe roll drivers 216 are removably mounted to the base in a manner thatdelivers motion from the motors to the finger drivers and roll drivers.Spring latches 255 (FIG. 1A) are positioned to engage the finger driveassembly 200 and roll drivers 216 with the base 218 when they are placedon the base in the proper orientation. Alignment features 215 (FIG. 1C)on the upper surface of the base unit 218 mate with or contactcorresponding features at the lower surface of the finger drive assembly200 and roll drivers 216. The alignment features help align theassembled components and to prevent components mounted to the base 218from sliding relative to the surface of the base during use.

The base unit 218 can be a reusable component isolated from the sterilefield using a sterile drape or bag (not shown), whereas the finger driveassembly 200 and roll drivers 216 may be manufactured as single-usecomponents or re-usable components for a number of times prior todisposal. Re-usable components may be designed for autoclaving or otherforms of sterilization.

Command interfaces 250 are provided for each of the tubular fingers 214.The command interfaces 250 include instrument boxes 252 that support theinstrument handles. The command interfaces 250 are user input devicesthat generate signals in response to the user's manipulation of theinstrument handle (e.g. pan, tilt and roll) and/or other user inputs.

In response to signals generated at the command interface 250, thesystem's motors are controlled to cause the finger driver and rolldriver to drive the fingers and instrument in accordance with the userinput.

Referring to FIG. 1B, the system 2 is supported by a support arm 204extending from a patient-side cart 205, the operating table 206, aceiling mount, or another fixture that positions the arm 204 where itcan support the finger and roll drivers, the associated motors, and thecommand unit near the operating table, allowing the surgeon to standpatient-side with his/her hands on the instruments 100. The arm may beone allowing repositioning of the system 2 in multiple degrees offreedom. While a robotically-controlled arm could be used with thesystem 2, since control and manipulation of the instruments is achievedusing the system 2 rather than maneuvering of the arm 204, the arm maybe much simpler in design and smaller in size than those used forconventional robotic surgery. The illustrated arm 204 is manuallypositionable about multiple joints and lockable in a selected position.Multiple degree of freedom movement allows the user to position thesystem 2 to place the insertion cannula 212 and the command interfaces250 in the desired position relative to the patient and the surgeon. Thecart 205 can be used to carry other equipment intended for use with thesystem 2, such as components supporting visualization, insufflations,stapling, electrosurgery, etc. The arm 204 has internal springs whichcounterbalance the weight of system 2, allowing it to remain stable inspace while the arm is unlocked, and reduces the force required to movethe system. While many joint combinations are possible the four barlinkages shown in the pictured embodiment allow for the system 2, topivot about the center of gravity, which reduces the force required toreposition the system.

The system's power supply, computer and user controls (e.g. touch screencomputer 201), which are discussed with respect to the system schematicat FIG. 18, may be mounted on the cart 205 with their associated cablingrouted through the arm 204 to the base unit 218.

A brief overview of the manner in which the system 2 is used willfacilitate an understanding of the more specific description of thesystem given below. During use, the fingers 214 and a portion of theinsertion tube 212 are positioned through an incision into a bodycavity. The distal end of a surgical instrument 100 is manually,removably, inserted through an instrument box 252 of command interface250, and the corresponding roll driver 216 and into the correspondingtubular finger 214 via the finger drive assembly 200. The instrument ispositioned with its distal tip distal to the distal end of the tubularfinger 214, in the patient's body cavity, and such that the handle 104of the instrument is proximal to the command interface 250.

The user manipulates the handle 104 in an instinctive fashion, and inresponse the system causes corresponding movement of the instrument'sdistal end. The motors associated with the finger driver are energizedin response to signals generated when the user moves the instrumenthandles side-to-side and up-down, resulting in motorized steering of thefinger and thus the instrument's tip in accordance with the user'smanipulation of the instrument handle. Combinations of up-down andside-side motions of an instrument handle will steer the instrument'stip within the body cavity up to 360 degrees. Manual rolling of theinstrument handle about the instrument's longitudinal axis (and/ormanually spinning of a rotation knob or collar proximal to theinstrument handle) results in motorized rolling of distal part of theinstrument's shaft 102 (identified in FIG. 11) using the roll driver216.

Finger Drive Assembly

Referring to FIGS. 1A, 1C and 1D, the insertion tube 212 of the fingerdrive assembly 200 is an elongate tube positionable through an incisionin a body cavity. The system is arranged such that multiple instrumentsmay be introduced into the body cavity via the insertion tube. Theillustrated embodiment allows for simultaneous use of three or fourinstruments—two that are actively steered using the tubular fingers 214,and one or two that enter the body via passive ports in the finger driveassembly 200. Different numbers of active channels (steerable fingers214) and passive ports may instead be used in the system withoutdeparting from the scope of the invention. For example, an alternativesystem might include a single steerable finger 214 and no passive ports,or the illustrated system might be modified to add one or more steerablefingers 214 or to add or eliminate passive ports.

Deployment Mechanism

The finger drive assembly 200 has a deployment mechanism that isoperable to simultaneously or independently reposition the distalportion of each finger 214 to increase or decrease its lateralseparation from the longitudinal axis of the insertion cannula 212. Thedeployment mechanism moves the fingers 214 between an insertion positionin which the fingers are generally parallel to one another forstreamlined insertion, and one or more deployed positions in which thefingers are pivoted laterally away from the longitudinal axis of theinsertion tube as shown in FIG. 1A. U.S. Publication Nos. US2007-0299387 and US 2011-0230723 illustrate deployment mechanisms thatcan be used for the system 2.

The first embodiment uses a deployment mechanism shown in FIG. 2A usingpivotable links 12 for this purpose, with each link 12 pivotably coupledbetween a finger 214 (only a portion of which is shown in the figure)and one or more elongate members 14, which can slide relative to (and,in the illustrated embodiment, partially within) the insertion tube 212.Additional links 16 may extend between the distal end of the insertiontube 212 and the fingers 214, providing additional support for thefingers. In the drawings, these additional links 16 have a rectangularcross-section with their long edges oriented to resist bending when thefingers are loaded—such as when instruments in the finger are being usedto grasp and elevate tissue. The proximal ends of the links 16 form ahinge coupled to the insertion tube as shown.

As shown in FIGS. 2B and 2C the proximal ends of the members 14 areconnected to a block 18 moveable relative to the finger drive assembly'shousing 210 between distal and proximal positions to slide the members14 between distal and proximal positions. Sliding the members 14 in thisway causes the link arms 12 to pivot and to thereby move the fingerslaterally.

A ratchet feature 224 (FIG. 2B) is used to retain the longitudinalpositioning of the block 18 relative to the housing 210 and to therebymaintain the fingers 214 in a selected deployment position. To deploy,and otherwise alter the lateral spacing of the fingers, the userdisengages the ratchet and slides the block 18 proximally or distally tomove the fingers from a first position to a second position. Re-engagingthe ratchet causes the ratchet to engage the fingers in the secondposition. A spring (not shown) biases the ratchet in the engagedposition. Other features relating to deployment and ratcheting aredisclosed in US Publication No. US 2011-0230723.

The system 2 may include features that allow it to sense changes in theposition of the deployment mechanism as an indicator of the finger'spositions relative to the longitudinal axis of the insertion tube 212.

As shown in FIG. 2B, pulleys 20 are rotatably mounted on the housing210. Each pulley 20 is coupled by a link arm 22 to the block 18, suchthat longitudinal movement of the block 18 to deploy the fingers 214causes the pulleys 20 to rotate. At least one of the pulleys 20 includesa magnet 24 on its shaft, as shown in FIG. 2C, in which magnets 24 areshown positioned on the shafts of each pulley 20. The magnet 24 includesdiametrically positioned north and south poles and preferably facesdownwardly towards the base 218.

Encoder chips 26 (FIG. 1C) on a distal portion of the base 218 (FIG. 2)are positioned to align with the magnets 24 when the finger driveassembly 200 is mounted on the base 218. When the deployment mechanismis utilized, each encoder chips 26 senses the rotational position of thenearby magnet 24, which indicates the rotational position of the pulley20 and thus the longitudinal position of the block 18. This informationallows the system to know the state of deployment (i.e. the lateral orx-axis position) of the finger 214. Signals generated by the encoderchips 26 may be used by the system to coordinate proper transformationbetween a user's input instruction and the corresponding outputcommands.

In alternative embodiments, each finger may be independently deployedusing a separately moveable sliding member 14, so as to allow eachfinger to be laterally repositioned independently of the other finger.

Although the first embodiment uses a manual deployment mechanism, in amodified system, one or more motors may be used to drive the deploymentmechanism. In some such systems, motor-driven deployment might beperformed independently of the steering of the fingers. In others, thesystem might dynamically control both the deployment mechanism and thefinger drivers as a means to move the fingers into target positions andorientations based on the user's positioning of the instrument handlesat the command unit 250. Control of the deployment mechanism and thefinger drivers at a given point in time can be based on the calculatedcurrent position and orientation of the fingers using signals from theencoder chips 26 together with other sensed information described below.

Instrument Pathways

Referring to FIG. 1D, the finger assembly's housing 210 has a generallyu- or v-shaped configuration, which each “leg” of the u- or v-shapedhousing the finger drivers associated with a different one of thesteerable fingers 214. While not a requirement, this shape leavesworking space between the “legs” for additional instruments, as isdiscussed below.

Ports 222 for the instruments 100 are positioned at the proximal end ofeach leg of the u- or v-shaped housing. These ports 222 may have sealsdisposed within the housing 210 to prevent loss of insufflation pressurethrough the ports 222 when no instruments are present in the portsand/or to seal around the shafts of instruments disposed in the ports.Additionally detachable seals may be placed proximal to the ports 222.One example of this configuration of seals is illustrated in FIG. 15.

Each port 222 defines the entrance to an instrument path through thehousing 210 and insertion tube 212 into a corresponding one of thesteerable fingers 214. The instrument path includes a tube or series oftubes extending from the port 222, through housing 210 and insertiontube 212, and out the distal end of the insertion tube 212 to form thefinger 214. The instrument path 221 has a proximal tube 221 a thatextends distally from the port 222, and a distal tube 221 b whoseproximal end is positioned over the proximal tube 221 a and whose distalend extends through the housing 210 and insertion tube 212. Centrallumen in the proximal and distal tubes 221 a, 221 b are continuous toform the instrument path 221. The actuation elements or cables 223 usedto steer the finger 214 extend through lumen in the distal tube 221 b asshown.

Passive ports 220 (two are shown) are positioned to allow passage ofadditional instruments through the housing 210 and the insertion tube212. In the drawings, these additional ports 220 are shown positioned inthe crotch of the u- or v-shaped housing 210. These ports allowinstruments such as scopes, rigid instruments and other instruments tobe passed through the insertion tube and used simultaneously with theinstruments deployed through the steerable fingers 214. Seals (notshown) in these ports 220 are positioned to prevent loss of insufflationpressure through the ports when no instruments are present in the ports,and also to seal around the shafts of instruments disposed in the ports220.

Finger

Referring again to FIG. 1, each finger 214 includes a deflectable distalportion 216, which may be formed of a plurality of vertebrae or links asshown, or flexible tubing, slotted or laser-cut metal tubing, or othermaterials capable of being steered without kinking or buckling. Examplesof steerable channels that may be suitable for use as steerable finger214 are shown and described in US 2011/0251599 and the otherapplications referenced herein. A flexible sleeve/liner (not shown)covers the deflectable distal portion 216 to avoid capture of tissue ingaps between vertebrae or slots.

The distal end of each the finger 214 may be equipped with a telescopingreinforcement feature positioned on its distal end such that as aninstrument tip exits the distal end of the finger, the reinforcementexpands distally in a longitudinal direction—surrounding the portion ofthe instrument tip that extends beyond the end of the finger 214. Thisfeature helps support any portion of the instrument shaft that extendsbeyond the distal end of the finger 214, thus avoiding undesirableflexing of the instrument shaft within the body cavity.

The fingers 214 are steered through selective pulling and/or pushing ofthe actuation elements 223 (e.g. wires, cables, rods, etc). In thisdescription the term “cable” will be used to represent any such type ofactuation element. The cables 223 are anchored at the distal endportions of the steerable fingers 214 and extend proximally through thesteerable fingers 214 into the housing 210. The number of cables to beused in a steerable finger may vary. For example, each steerable fingermay include two or four cables, wherein distal portions of the cablesare arranged 180 or 90 degrees apart, respectively, at the distal end ofthe finger. In other embodiments, three cables may be used for eachfinger.

In the illustrated embodiment four cables are used. By “four” actuationcables it is meant that there may be four separate cables/wires etc ortwo cables/wires each of which has a U-turn anchored at the distal endof the finger such that four cable proximal ends are disposed within thehousing 210. Additional cables that are not used for actuation may bepositioned through the fingers and used to provide feedback as to theposition of the tips of the corresponding fingers, using methods tothose similar to those described below.

Finger Driver

This section describes the finger driver for one of finger 214 shown inFIG. 1A. It should be understood that the steerable finger shown on theright side is manipulated using a finger driver having similar features.

The proximal end of each cable 223 extends out of the proximal end ofthe tube 221 b and is engaged to a pulley 232 a or 232 b. Each pulley232 a, 232 b includes a spur gear 231 a, 231 b as shown. While thedrawings show the axes of rotation of the 232 a, 232 b pulleys to benon-parallel relative to one another, in other embodiments the pulleysmay be oriented to have parallel axes of rotation.

A first pair of the pulleys 232 a is engaged to two cables 223 that areanchored at points separated by 180 degrees at the distal end of thecorresponding steerable finger. The components in the finger drivers arearranged so that each steering motor in the base unit drives one suchpair of the cables—although in other embodiments each cable has adedicated steering motor. To allow each steering motor to drive twocables, each finger driver 203 is arranged with a first gear 230 adisposed between and engaged with the teeth of the gears 231 a on thefirst pair of pulleys 232 a, such that rotation of the gear 230 a in afirst direction (by action of a steering motor as is discussed below)tensions one cable in the pair and reduces tension on the other cable inthe pair, thus deflecting the distal end of the corresponding steerablefinger in a first direction. Similarly, rotation of the gear 230 a inthe opposite direction (by reversing operation of the correspondingsteering motor) deflects the distal end of the steerable finger 214 (notshown) in the opposite direction by tensioning the opposite cable. Asecond pair of the pulleys 232 b is similarly driven by a second gear230 b disposed between and engaged with the teeth on the gears of thesecond pulleys 232 b. The cables associated with the second gear 230 bare also preferably arranged 180 degrees apart at the distal end of thesteerable finger (and offset 90 degrees from the cables associated withthe first gear 230 a) allowing for 360 degrees of deflection of thesteerable finger 214.

The pulleys 232 a, b and gears 230 a, b are housed within a sealedpulley box 219. The proximal end of the tube 221 b and the full lengthof the tube 221 a (FIG. 4) are housed within the sealed box 219. Eachpulley box is mounted within the housing 210 of the finger driveassembly 200 and oriented with the port 222 exposed at the proximal endof the housing 210 and with the tube 221 b extending into the insertiontube 212. Seals surround the port 222 and tube 221 b to seal the pulleybox against passage of moisture and contamination into the spacesurrounding the gears and pulleys during cleaning.

FIGS. 5A-5C show one embodiment of a pulley 232 a. Each such pulleyincludes a spool 225 rotationally fixed to a shaft 227. Gear 231 a ispositioned on the shaft 227 and can spin relative to the shaft 227. Thepulley 232 a is sprung by a coil spring 229 disposed around the shaft,with one end of the spring 229 attached to the gear 231 a and the otherend attached to the spool 225. The spool includes a pair of posts 235spaced 180 degrees apart. The gear has a pair of stops 237 spaced 180degrees apart and separated by an annular space 241. The posts 235 ofthe spool 225 extend into the annular space 241.

The cable 223 is wound on the spool 225. Each pair of the cables istensioned such that when a finger is in a straight orientation asschematically shown in FIG. 6A, each post 235 is positioned against oneof the stops 237. When a motor is used to drive the pulleys to bend thefinger to the left as shown in FIG. 6B, the gear 231 a of the pulley 232a on the left spins in a clockwise direction, and as it spins its stops237 remain in contact with the posts 235 of the corresponding spool—thusthe gear and spool move as a solid body. Rotation of the spool tensionsthe cable 223L, causing the finger to bend to the left as schematicallyshown. At the same time, the gear of the pulley 232 a on the right spinsin a counter-clockwise direction and the cable 223R slackens due tocompliant members of the cable transmission and body. As the gear spins,its stops 237 rotate away from the posts 235 of the corresponding gear.Because the gear 231 a and spool 225 are connected by the spring 229(FIG. 5C), the spring force eventually acts on the spool to rotate itcounter-clockwise, thus taking up extra slack in the cable 223R.

Output from sensors associated with the pulleys is used to calculate theposition of the tips of the fingers, force on the cable or finger tip byextension, and to provide redundant sensing of the position of thefinger tip relative to that sensed by the motor's encoder. The followingdiscussion of the use of the sensors will focus on the situation inwhich a finger is pulled to the left as in FIG. 6B, but it should beunderstand that the same principles apply for each direction in whichthe finger is steered.

In general, the system makes use of the passive cable in each cable pair(a cable pair being a pair of cables tensioned by a common one of thegears 230 a, 230 b) to provide positional feedback corresponding to theposition of the tip of the corresponding finger. Referring to FIGS. 4Band 5A, each pulley 232 a, 232 b has disk magnet 243 having adistally-facing surface having diametrically positioned north and southpoles. Encoder chips 245 in the base unit 218 (FIG. 8A, discussed below)are positioned to detect the rotational position of each such magnet.When the finger is steered to a bent position, such as the left-wardbend in FIG. 6A, the cable 223L tensioned to produce the bend undergoeselastic stretching under load, and also deforms the shaft of the tubularpassage 221 through which the cable extends. Thus the distance thatcable 223L was withdrawn to cause the bend does not correspond directlyto the amount by which cable 223R has advanced in response to bending.Since the passive cable 223R is not under the high loads beingexperienced by the active cable, the distance that the passive cable223R advanced (as indicated by the degree of rotation of the magnet 243sensed by the encoder chip), reflects the amount by which the finger isbent and can be used by the system to derive a more accurate measurementof the position of the finger in three dimensional space. This system isbeneficial in that it eliminates the need for a cable, pulley and sensorarrangement devoted solely position sensing.

Moreover, the difference between the amount by which the active cable223L was withdrawn and the passive cable 223R advanced represents theamount of force applied by the active cable 223L at the instrument tip.While feedback as to the force at the tip also comes from measuringcurrent on the steering motors, the force at the tip provides a moredirect measure of the force.

Feedback from the motor's encoder can be compared with the positionalinformation obtained from the magnet associated with cable 223L and usedto detect whether there is an error in the system. For example, if theposition measured at the motor is significantly different from theposition derived from the positions of the magnets 243, the system mightalert the user to the possibility that the active cable 223L is brokenand disable the system 2.

If the pulley associated with an active cable is determined to haverotated out of its normal range of motion to its extreme relaxedposition (e.g. to a position against the stop 237 opposite to the stopit should be positioned against in order to be driven by the gear), itwill indicate an error in the system that might potentially be an errorin the system. Feedback indicating that both pulleys in a pulley pairare in a relaxed state, or have both rotated to a position against astop when one of the cables is tensioned, is indicative of a brokencable. When error conditions are detected the system, the system maydisengage the motors and deliver an error message to the user via thecomputer interface 201.

Motion Transfer—Base Unit to Finger Drivers

The finger driver 203 receives motion from the steering motors 236 a, bin the base unit 218 through rotational coupling between elements on thefinger drive assembly and elements on the base 218. On the finger driveassembly 200, members such as driven shafts 226 a, 226 b (FIG. 7A) areexposed on the bottom of the housing 210. Each of the driven shafts 226a, 226 b is rotationally fixed to and axially aligned with the one ofthe gears 230 a, 230 b (FIGS. 4A and 4B) within the housing 210, suchthat rotating each driven shaft 226 a, 226 b rotates the correspondinggear 230 a, 230 b, thus steering the steerable finger 214 as describedabove. The driven shafts 226 a, 226 b may extend from or be recessed atthe lower surface of the housing 210.

As shown in FIG. 7B, second members such as drive shafts 228 a, 228 bare exposed at the upper surface of the base 218 and may extend from orbe recessed at the upper surface of the base 218. Each drive shaft 228a, 228 b is releasably engageable with a corresponding one of the drivenshafts 226 a, 226 b on the bottom of the housing 210 (FIG. 7A). Drivenshafts 226 a, 226 b (FIG. 7A) and drive shafts 228 a, 228 b (FIG. 7B)are designed for mating engagement or any alternative form of engagementthat will allow for the transmission of torque from each drive shaft toits corresponding driven shaft. In the arrangement shown in thedrawings, driven shafts 226 a, 226 b are male components that mate withdrive shafts 228 a, 228 b as their female counterparts. The illustratedmale components include hex ball heads of spherical hex keys and thefemale components include hex sockets for receiving the hex heads. Inthis embodiment the rotational axis of each first member 226 a, 226 bangularly intersects the rotational axis of the corresponding driveshaft 228 a, 228 b. In other embodiments, however each first membermight share a common rotational axis with the corresponding drive shaft.

While the driven shafts and drive shafts are shown as hex mating pieces,any alternative engagement features that will likewise allowtransmission of torque from the drive shafts 228 a, 228 b to the drivenshafts 226 a, and 226 b can instead be used.

To facilitate engagement between the drive shafts 228 a, b and thedriven shafts 236 a,b, the drive shafts 228 a,b are downwardlydisplaceable into the base unit 218 when first contacted by the drivenshafts 226 a,b. Springs bias the drive shafts 228 a, b in theiroutermost position, so that they will spring upwardly once matingfeatures of the drive shafts 228 a, 228 b and driven shafts 226 a, 226 bengage. Sensors may be positioned in the base unit 218 to sense wheneach shaft has returned to its fully extended position, allowing thesystem to know whether any of the drive shafts 228 a has not properlyengaged with the corresponding driven shaft 226 a. This sensedinformation may be used to lock out use of the system until all shaftsare properly engaged. It can also be used to initiate minor rotation ofthe steering motors associated with the shafts 228 a that have notsprung upwardly, to allow the hex head of the shaft 228 a to move to anorientation where it will engage with the hex socket of thecorresponding shaft 226 a.

As will be evident from the following section, engaging the drivenshafts and drive shafts allows for the transfer of motion from thesystem's steering motors to the pulleys that manipulate the cables forsteering the fingers.

Base Unit

The base unit 218 houses steering motors 236 a, b and a roll motor 238.The illustrated system has a u- or v-shaped configuration similar tothat of the housing 210. The base unit 218 is organized such that motorsassociated with steering the left-side finger 214 and with axiallyrolling an instrument extending through the left-side finger 214 are inthe left side of the base unit 218 (e.g. in the left leg of the v- oru-shaped housing), and such motors associated with the right-side fingerand its instrument are in the right side of the base unit. The computercontrollers, motor drivers, and associated electronics for each side ofthe system are also housed within the base unit 218. In this embodiment,two computer controllers/real time processors are included in the baseunit 210, each associated with one of the fingers, although in otherembodiments a single real time processor may be associated with bothfingers. Communication between these computers and the user interfacecomputer (e.g. touch screen computer 201 of FIG. 1A) may use an ethernetTCP/IP connection through a router, or other means. In otherembodiments, a touchscreen processor and real time processor are housedwithin a single computer, eliminating the need for the router.

FIG. 8A shows an arrangement of the motors 236 a, b, 238 and theircorresponding gear assemblies within the base unit's housing (notshown). Each steering motor 236 a, b housed within the base 218 drivesthe gears of its corresponding gear assembly 240 a, b.

A gear in each gear assembly 240 a, 240 b is rotationally fixed to oneof the exposed drive shafts 228 a, 228 b so that activation of themotors 236 a,b produces axial rotation of each of the drive shafts 228a, 228 b. Two such steering motors 236 a, b, are shown for each finger,each with a corresponding gear assembly 240 a, b. Motor 236 a ispositioned to drive gear assembly 240 a to produce axial rotation ofdrive shaft 228 a. Motor 236 b drives gear assembly 240 b to produceaxial rotation of drive shaft 228 b.

Referring again to FIG. 8A, the output of roll motor 238 in the baseunit is coupled by way of gear assembly 242 to a member such as a rolldriving shaft 244, so as to cause axial rotation of the roll member 244when the roll motor 238 is operated. The roll driving shaft 244 may besimilar in configuration to the drive shafts 228 a, 228 b.

Roll Driver

The roll driver 216 (FIGS. 1A, 1B and 9) includes a housing 217. Asshown in FIG. 10, a roll drive tube 248 is axially rotatable within theroll driver housing 217 (not shown in FIG. 10). Roll drive tube 248includes a lumen for receiving a portion of the shaft of instrument 100(FIG. 1A). The exterior of the roll drive tube 248 forms a worm gear,which engages with a roll gear assembly that includes an adjacent wormgear 249. The roll gear assembly includes a member such as driven rollshaft 234 that is exposed at the lower surface of the housing 217 (notshown). The driven roll shaft 234 is axially rotatable relative to theroll driver housing 217.

The roll driver 216 is positionable on the base unit 218 such that thedriven roll shaft 234 rotationally engages with the roll driving shaft244 (FIG. 7B) of the base unit 218. This rotational engagement allowstransfer of torque from the shaft 244 to the shaft 234—thus allowingrotation of the roll drive tube 248 (and thus the instrument shaft)through activation of the roll motor 238. The shafts 234, 244 may bemating pieces similar to those described for the driven shafts and driveshafts 226 a, b and 228 a, b used for steering.

The roll drive tube 248 has features designed to rotationally engagewith corresponding features on the surgical instrument shaft. Thisengagement allows axial rotation of the roll drive tube 248 to produceaxial rotation of the distal portion of the instrument shaft. Preferredfeatures are those that create rotational engagement between theinstrument shaft and the roll drive tube 248, but not sliding orlongitudinal engagement. In other words, the features are engaged suchthat axial rotation of the roll drive tube 248 axially rotates theinstrument shaft, but allow the instrument to be advanced and retractedthrough the roll drive tube 248 for “z-axis” movement of the instrumenttip. Rotational engagement between the instrument shaft and the rolldrive tube 248 should preferably be maintained throughout the usefulrange of z-axis movement of the instrument tip (e.g. between a firstposition in which the instrument tip is at the distal end of the fingerto a second position in which the instrument tip is distal to the distalend of the finger by a predetermined distance.)

Engagement features for the instrument 100 and roll drive tube 248include first surface elements on a drive segment 260 of the shaft 102of the instrument 100 (FIG. 11) and corresponding second surfaceelements on the inner surface of the roll drive tube 248 (FIG. 10).Examples of surface elements 256, 258 are shown in FIGS. 12A-14.Referring to FIGS. 12A and 12B, the drive segment 260 of the instrumentshaft 102 includes first surface elements 256 in the form of splines orribs extending radially from the instrument shaft and longitudinallyalong the shaft. The lumen of the roll drive tube 248 includes secondsurface elements 258 in the form of longitudinally extending ribs (alsovisible in FIG. 12B). The surface elements 256, 258 are positioned suchthat when the roll drive tube 248 is rotated, second surface elements258 on the interior lumen of the roll shaft contact and cannotrotationally bypass the surface elements on the instrument shaft. Thedistal ends of the splines 256 may be tapered such that they arenarrower (in a circumferential direction) at their distal ends than theyare further proximally, to facilitate insertion of the splines/ribsbetween corresponding ones of the ribs while minimizing play between thesplines 256 and adjacent ribs 258 as the roll shaft rotates theinstrument shaft. The longitudinal length of the splines 256 is selectedto maintain rotational engagement between the instrument shaft and theroll shaft throughout the desired z-axis range of motion.

The drive segment 260 of the instrument shaft may have a larger diameterthan proximally- and distally-adjacent sections, as shown in FIG. 11. Tofacilitate insertion of the drive segment 260 into the roll drive tube248, the drive segment 260 includes a chamfered distal edge 262.

As another example, shown in FIGS. 13A-13C, the drive segment 260 has ahexagonal cross-section and the roll drive tube 248 has longitudinalgrooves with v-shaped radial cross-sections as shown. Edges 256 a of thedrive segment 260 formed by corner regions of the hexagonal crosssection seat in troughs 258 a so as to permit longitudinal sliding ofthe instrument through the lumen but prevent rotation of the instrumentwithin the lumen.

In another embodiment shown in FIG. 14, drive segment 260 includeslongitudinally extending grooves 256 b. One or more pins 258 b extendradially inwardly from the luminal wall of the roll drive tube 248 andinto engagement with one of the grooves 256 b.

It should be noted that the instrument 100 is preferably constructed sothat the roll drive tube 248 will cause rolling of the drive segment 260and all portions of the instrument shaft 102 that are distal to it(including the end effector), without causing axial rolling of theinstrument handle 104. Thus the handle and shaft are coupled together ina manner that permits the instrument shaft to freely rotate relative tothe handle when acted upon by the roll drive tube 248. For example, theinstrument 100 might includes a roll joint within, or proximal to, thedrive segment.

Tubular Connectors

Openings 264 and 266 (FIG. 1C) at the proximal and distal surfaces ofthe roll driver housing 217 allow passage of an instrument shaft throughthe lumen of the roll drive tube 248. If, as in the first embodiment,the finger drive assembly and the roll drivers are separate components,any gap between the components is bridged by a tubular connector 268mounted between the distal opening 266 of the roll driver housing 217and the proximal port 222 of the housing 210 so as to provide acontinuous instrument path. The tubular connector 268 can be removablyconnected to the roll driver housing 217 and the housing 210, or itmight be more permanently connected to one or both of them. There mayalso be a similar tubular connector between the instrument box 252 andopening 264 on the roll driver to guide the instrument shaft into theroll driver.

Referring to FIG. 15, the tubular connector 268 may include a luer port274 for use as a flush port or for directing insufflation gas throughthe finger drive assembly 200 and into the body cavity. A valve 270 suchas a cross-slit valve is positioned within the tubular connector 268 toprevent loss of insufflation pressure through its proximal end, when noinstrument is present. A second seal 272 is positioned to seal againstthe shaft on an instrument that passes through the tubular connector,thus minimizing loss of pressure around the shafts of an instrumentdisposed through the connector 268. In other embodiments, the luer port274, valve 270, and seal 272 may be disposed in the housing 210. Asingle seal, or other seal configurations may also be utilized to sealwith and without an instrument present.

Command Interface

Referring again to FIG. 1A, the base unit includes a command interface250 equipped to generate signals corresponding to the position of,and/or a change in the position of, a proximal part of the surgicalinstrument 100 when the handle 104 is manually moved by a user (as wellas other signals discussed below). The system generates control signalsin response to the signals generated at the command interface. Suchcontrol signals are used to drive the motors 236 a, b, 238 to steer thefingers and roll the instrument's shaft in accordance with the user'smanipulation of the instrument handle. Thus, manual movement of theinstrument handle by the user results in motor driven steering of theinstrument's distal end and motor driven axial roll of the instrumentshaft.

In this embodiment, it is the instrument's handle 104 (FIG. 1) whosemovement triggers the signals of the command interface that result insteering of the fingers and rolling of the instruments. In otherembodiments, a proximal portion of the instrument shaft, or anothercomponent of the instrument can be used. Still other embodiments use aseparate user input device to generate the signals inputting the desiredposition of the instrument, rather than user input devices that respondto the user's movement of the instrument handle itself.

Turning to FIG. 16, the command interface 250 includes a first portionor bracket 276 a that is anchored to the base 218 (not shown) androtatable about an axis A1 (which may be generally normal to the surfaceof the base). A second portion or bracket 276 b is mounted to the firstbracket 276 a and is rotatable about axis A2 (which may be generallyparallel to the surface of the base and perpendicular to A1).

The instrument box 252 is positioned on the second bracket 276 b asshown in FIG. 1. Referring again to FIG. 1A, the instrument box includesa housing 253 a removably attached to the second bracket 276 b, so thatthe instrument box may be detached after surgery for disposal orsterilization and reuse. A passage 275 for the surgical instrument 100extends through the housing as shown. As shown in FIG. 16, in the firstembodiment, an opening 253 b in the housing 253 a is slidable over theproximal portion of the second bracket 276 b. A spring latch 255 (FIG.1A) between the instrument box 252 and bracket 276 b engages the twocomponents once the instrument box 252 has been advanced to the properposition.

The instrument box 252 is configured to receive the surgical instrument100 and to allow the instrument shaft to slide relative to theinstrument box 252 during z-axis positioning of the instrument. Thearrangement of the first and second brackets 276 a, 276 b with theinstrument box 252 (and therefore the instrument 100) renders theinterface 250 moveable about the axes A1, A2 when the user moves theinstrument handle. Up-down movement of the instrument handle results inpitch movement of bracket 276 b about axis A2, and side-side movement ofthe instrument handle results of yaw movement of bracket 276 a aboutaxis A1, with combined up-down and side-side movement resulting incombined pitch and yaw motion.

Encoders within the command interface 250 generate signals in responseto movement about the axes A1, A2. In particular, a first encoder ispositioned such that it will generate signals corresponding to yawmovement of first bracket 276 a (about axis A1). A second encoder ispositioned to generate such signals corresponding to pitch movement ofsecond bracket 276 b (about axis A2). Types of suitable encoders includeoptical or magnetic incremental rotary encoders that generate signalscorresponding to the speed and the incremental amount of angularmovement are suitable for this purpose. Signals generated by theseencoders are received by electronics housed within the base unit 218 andused to control and drive the steering motors 236 a, b (FIG. 7B).

The instrument box houses components that cause several types of userinput signals to be generated by the system in response to user action,including: (a) signals representing the amount by which the user axiallyrotates the instrument handle or an associated roll knob; (b) signalsindicating proper placement of an instrument 100 into engagement withthe system at the instrument box; (c) signals from a user-operableengage/disengage button that lets a user selectively engage or disengageoperation of the command interface 250 from activation of the motors;and (d) signals generated in response to z-axis movement of theinstrument to indicate the z-axis position of the instrument 100.

Referring to FIG. 17A, the instrument box 252 includes an elongate tube278 having a knob 254 on its proximal end. A lubricious inner tube 279extends through the elongate tube 278 and has a proximal block 282surrounded by the knob 254. The block 282 supports one or more exposedmetallic elements, such as the proximally-facing metallic elements 284.A magnetic sensor 286 is within the block 282. An opening in the block282 is positioned to receive the shaft of an instrument 100 so thatinstrument shaft can pass tube 278. A spring loaded pin 281 extends intothe opening in the block 282.

In FIG. 17A, the handle of instrument 100 is shown only partiallyadvanced towards the knob 254 to allow certain features to be visible. Acollar 106 is located on a proximal portion 108 of the instrument'sshaft. The distal side of the collar 106 is most easily seen in FIG.11B. It includes a distal part having a notch 109. A magnet 110 in thecollar 106 faces distally. These features are located such that when auser advances the instrument 100 through the opening in the block 282with the notch 109 facing the pin 281, the notch 109 captures the pin281 to rotationally engage the instrument handle to the block 282. Themagnet 110 magnetically adheres to the metallic elements 284 whenbrought into proximity to them, thus retaining the instrument inposition against the block 282.

The sensor 286, which may be a Hall sensor, is positioned so that itwill generate an instrument presence signal when the magnet 110 ispositioned at the metallic elements 284. This signal alerts the systemthat an instrument is properly positioned at the command interface 250and the system is therefore ready to control the steerable fingers andthe instrument roll position when the user is ready to do so.

The system may therefore be configured such that the motors used tosteer a given finger will not be activated in the absence of aninstrument presence signal from the sensor 286, unless the userotherwise overrides this feature. This feature prevents inadvertentmovement of a finger when there is no instrument extending through it.

A user actuated switch is positioned to generate a signal indicatingwhether the user wishes to place the system in an “engaged” state. Theswitch may be located near the users hand for easy access, such as onthe instrument box 252, the instrument, or elsewhere on the system 2.Alternatively, the switch may be a foot pedal or voice activatedcircuit.

In the first embodiment, the switch is actuated using a button 288positioned adjacent to the knob 254 and supported by a button assembly(not shown). A magnet (not shown) is carried by the button assembly.When the engage button 288 is pressed, the button assembly moves themagnet into or out of alignment with a Hall sensor, causing the Hallsensor to generate a signal that the button has been pressed. Whenpressure on the button 288 is released, a spring (not shown) returns thebutton to its original position. Feedback is provided to the user whenthe system is moved in and out of the engaged state. For example, an LED245 on the instrument box can turn on, or change color, when that partof the system is engaged and turn off when it is disengaged. An auditorytone might additionally be sounded when the system is moved between theengaged and not-engaged state. An electrical connector 99 (FIG. 17B) inconnected between the instrument box and the bracket 276 b to apply avoltage to the LED.

When the engage button has been pressed, the system moves from a “notengaged” state to an “engaged” state with respect to the instrument onthat side of the system. When in the engaged state (assuming instrumentpresence has been detected as discussed above), the system will activatethe motors in response to detected movement at the command interface250. Pressing that same engage button 288 again will generate anothersignal used by the system to move the system to a “not engaged” statewith respect to the instrument on that side of the system. When thesystem is in the “not engaged” state, the steering and roll motors willnot be activated and the orientation of the fingers 214 and the rolldrive tube 248 remain fixed. The instrument presence sensor 286 and theuser actuated engage button 288 are therefore useful safety andconvenience features designed to prevent activation of the steering androll motors 236 a,b, 238 even in the presence of detected movement atthe command interface 250. This is beneficial in a variety ofcircumstances, such as when the user wishes to remove his/her hand fromthe instrument handle without causing inadvertent movement of thefingers within the body as the command interface 250 shifts position oris inadvertently bumped. The user might also wish to disengage thesystem in order to maintain the orientation of a finger 214 within thebody cavity while s/he re-positions the command interface to a moreergonomic position, or while s/he replaces the instrument extendingthrough that finger with another instrument s/he wants to deliver to thesame location within the body.

If the user elects to change the position of the button 288 relative tothe instrument handle 104, s/he may do so by rotating instrument collar106 relative to rotation knob 254.

A cord (not shown) extending between the block 282, knob 254 or adjacentstructures may be used to carry signals from the instrument presencesensor 286 and the sensor associated with the user actuated button 288to circuitry in the base or command interface 250.

Roll Input

The instrument box 252 gives the user two ways in which to triggermotorized rolling of the instrument's shaft. The first way is to spinthe knob 254; the second way is to rotate the instrument handle 104. Inthe first embodiment, the rotation knob 254 is positioned near theinstrument handle 104, allowing the user to find the knob in a positionsimilar to the position of a rotation knob on a standard handinstrument.

Supports 290, 292 are mounted in fixed positions within the instrumentbox 252. A first gear 294 is rotationally engaged with the exteriorsurface of the tube 278, and a second gear 296 is adjacent to andengaged with first gear 294. Knob 254, tube 278, and thus gear 294 areaxially rotatable relative to instrument box 252, and their rotationproduces corresponding rotation of the second gear 296. Rotation of thesecond gear 296 produces rotation of a magnet positioned such thatrotational position of the magnet is sensed by an encoder in the commandinterface 250. There may be a sterile drape present between the magnetand encoder. Referring to FIG. 17B, the magnet is a disk magnet 300supported on a post 298. The post 298 extends distally from the secondgear 296 and rotates when the gear rotates. The magnet 300 includes adistally-facing surface having diametrically positioned north and southpoles.

When the instrument box 252 is mounted on the bracket 276 b, the post298 extends into a corresponding opening 302 (FIG. 16) in the bracket276 b. An encoder chip 304 is positioned within the opening 302 so as tosense the rotational position of the magnet 300 on the post 298 (whichindicates the rotational position of the knob 254). Signals generated bythe encoder chip 304 are used to generate drive signals for the rollmotor in response to rotation of the knob 254. Roll input is similarlygenerated through rolling of the instrument's handle. Because theinstrument's collar 106 is rotationally coupled to the tube 278 (viablock 282), rotating the instrument handle rotates the tube 278, andresults in the generation of a signal at the encoder chip 204 asdescribed above.

In an alternative embodiment, a rotatable knob on the instrument'shandle may be rotatable to generate the roll input signals in a similarmanner.

Because there is friction at the instruments roll joint 260 (FIG. 11A)between the distal portion 102 of the instrument shaft and the proximalportion 108 of the instrument shaft, rolling of the distal portion canresult in a slight roll of the proximal portion 108 which can generateroll input by the roll encoder chip 204. Referring to FIG. 17A, theinstrument box 252 is designed to apply friction against rotationalmovement of the gear 296 using an element positioned between theinstrument box 252 housing (or another fixed support within theinstrument box) and the gear 296 or post 298. A friction plate 247 has afirst face in contact with the proximal end of the gear 296 or post 298,and a second face in contact with the interior of the instrument box 252(not shown in FIG. 17A). The friction plate 247 imparts frictionalresistance against rotation of the gear 296. The amount of friction isselected such that it is more than the friction present between thedistal shaft 102 and the proximal shaft 108 at the instrument roll joint260. Rotation of the proximal portion of the instrument shaft 108resulting from friction at the roll joint 260 is thereby prevented frombecoming input to the roll encoder chip 204, thus preventing forwardfeedback.

Z-Axis Movement

Z-axis movement of the instrument to move the instrument tip proximallyor distally within the body cavity is manually performed bypushing/pulling the instrument handle 104. The instrument box 250 isconfigured so that the knob 254 and instrument handle 104 can be used togenerate instrument roll input regardless of the z-axis position of theinstrument handle relative to the instrument box 252. When theinstrument's collar 106 is coupled with the block 282, z-axis movementof the instrument (i.e. advancement and retraction of the instrumentbetween distal and proximal positions) causes the knob 254 and tube 278to likewise move along the z-axis—keeping the instrument and the rollinput features engaged throughout z-axis travel. A constant force spring320 (FIG. 17B) is connected between a collar 280 on a distal portion ofthe tube 278 and the support 290. When the instrument is advanced in adistal direction, the tube 278 pushes the collar 280 distally, againstthe force of the spring 320. When the user removes the instrument handle104 from the instrument box 252, the spring 320 retracts the tube 278and thus the collar 280 returns to the proximal position. When aninstrument is present the spring 320 force would be less than thefrictional force required to move the instrument, and the instrumentwould maintain position with no user input.

The instrument box may include a lock to prevent the tube 278 fromadvancing distally during insertion of an instrument into the tube 278.The lock may be a mechanical latch manually releasable by the user orelectronically released in response to a signal produced by theinstrument presence sensor.

The features of the instrument box allowing the z-axis position of theinstrument to be determined will next be described with continuedreference to FIG. 17B. A pin 308 extends laterally from the collar 280.A lever arm 310 has a first end having a slot 312 slidable over the pin308. A second end of the lever arm 310 is pivotably coupled to astationary lever arm mount 314 mounted within the instrument box. Amagnet 316 is positioned at the pivot axis of the lever arm 310, androtates as the lever arm 310 pivots. The magnet 316 includes adistally-facing surface having diametrically positioned north and southpoles.

Referring to FIG. 16, when the instrument box 252 is mounted on thebracket 276 b, the magnet 316 (FIG. 17A) is positioned in alignment withan encoder chip 318 mounted in the bracket 276 b. The encoder chip 318generates signals representing the rotational position of the magnet 316and thus lever arm 310, from which the axial position of the tube 278and thus the instrument 100 can be derived by the system.

A scaling factor is the amount by movement of the instrument or fingeris scaled upwardly or downwardly relative to the user's movement of theinstrument handle. The system 2 uses the determined z-axis position ofthe instrument to dynamically adjust the scaling factors used in controlof the steering motors. For example, smaller scaling factors might beused for steering when the instrument is fully extended from the fingerthan would be used when the instrument tip is closer to the tip of thefinger to give consistent steering relative to the user input regardlessof the instrument's z-axis position.

The first and second brackets 276 a, b of the command interface 250 maybe covered by sterile drape for use, while the instrument box 252remains external to the drape.

Electromechanical Block Diagram

FIG. 18A shows an electromechanical block diagram of the system 2, asslightly modified for an embodiment in which a roll input wheel ispositioned on the instrument shaft rather than on the instrument box asdiscussed above. Certain other features, including the deploymentsensor, are not shown, and in the FIG. 18A embodiment the roll driver isincluded as part of the base unit (labeled “Drive Assembly”) rather thanas a separate component.

Use

To use the system 2, the base unit 218 and the first and second portions276 a, 276 b of the command interface 250 are covered by a steriledrape. The housing 210 of the finger drive assembly 200 and roll driver216 are mounted to the base unit to engage the motor driven members 228a, 228 b, 244 of the base unit 218 with the driven members 226 a, b,234. The system monitors engagement between the shafts 228 a, 228 b, 244of the base unit with the shafts 226 a,b, 234 of the finger and rolldrivers, and shafts 228 a, 228 b, 244 found to not have not engaged withtheir counterparts may be rotated slightly through motor activation asdescribed in “Motion Transfer” section above.

The instrument box 252 is mounted to the second portion 276 b of thecommand interface 250. Spring latches 255 engage to secure the housing210 and roll driver 216 to the base unit 218 when the components areproperly aligned. Similar spring latches are engaged to secure theinstrument box 252 to the portion 276 b of the command interface.

Sterile tubular connectors 268 are coupled between the roll driver 216and the port 222 on the housing 210, and similar connectors may bepositioned between instrument box 252 and the roll driver 216. Once thesystem 2 is assembled, the distal end of the finger drive assembly 200is positioned within the body cavity of the patient. Alternately, thefinger drive assembly may also be positioned inside the patient and thenassembled to system 2. For easy insertion into the body cavity, thedeployment mechanism is used to position the fingers 214 in astreamlined side-by-side configuration using the links 12. The fingers214 and a portion of the insertion tube 212 are the passed through theincision into the body cavity. The distal tip of a medical instrument(e.g. forceps, graspers or other flexible shaft hand instruments) isinserted through the instrument box 252 and advanced distally. Advancingthe instrument causes the tip to exit the instrument box 252, passthrough the roll driver 216, then into port 222 on the proximal end ofthe finger drive assembly's housing 210, and through the correspondingfinger 214 until the distal end of the instrument extends from thedistal end of the finger 214.

When an instrument is fully inserted through the command interface 250,instrument presence signals are generated at sensor 286 (FIG. 17A).

Additional instruments such as scopes, graspers and the like are passedthrough the insertion cannula via ports 220 for use simultaneously withthe instruments deployed through the fingers.

The deployment mechanism is used to adjust the lateral spacing of eachfinger (and thus the instrument passed through it) relative to thelongitudinal axis of the insertion cannula as described with respect toFIGS. 2A through 2C.

Before the user can steer or roll the instrument using the system, s/hepresses the engagement button 288 to cause the system to enter into theengaged state.

At least when the system is placed in an engaged state, the systemsenses the positions of the brackets 276 a,b and the roll input magnet300 to determine the starting position of the instrument's handle 104.

If the system is in an engaged state and the instrument's presence hasbeen detected, the system will respond to steering and roll input at thecommand interface 250 by engaging the steering and roll motors to steerthe finger and roll the instrument. To steer the instrument 100 withinthe body, the user manipulates that instrument's handle 104. Forexample, to move the instrument's end effector upwardly, the user willlower the handle; to move the end to the left, the user will move thehandle to the right. (Although in alternate arrangements, the system maybe configured such that the end effector moves in the same direction asthe handle—so that, for example, raising the handle raises the endeffector). The encoders in the command interface 250 sense the movementor position of the handle by sensing rotation of the brackets 276 a, brelative to axes A1, A2. In response, the system generates controlsignals to activate motors 236 a, b to thereby steer the finger and theinstrument that extends through it. To axially roll the instrument, theuser axially rolls the instrument handle 104 or the rotation knob 254relative to the instrument box 252, producing signals at the rollencoder chip 304. In response the roll motor 238 is activated to rollthe distal part 102 of the instrument shaft. To position the instrumentfurther into the body cavity, the user pushes the instrument handle 104distally. This z-axis movement of the instrument is sensed by encoder318, and the z-axis position of the instrument may be used by the systemto dynamically adjust scaling factors for finger steering and/orinstrument roll.

FIG. 18B is a schematic of an exemplary drive control sequence forcontrolling the steering motors to drive the fingers based on sensedinformation (e.g. approximations of the positions of the fingers, thepositions of the user interface etc), using forward and reverse mappingand PID control.

Actuation of the instrument's end effector, such as the opening/closingof jaws, is carried out in conventional fashion using manual actuators(e.g. levers, knobs, triggers, slides, etc.) on the instrument handle.If desired, an instrument may be withdrawn from the system during theprocedure, and replaced with a different instrument, which again may besteered and axially rotated through manipulation of the handle asdescribed.

The first embodiment is but one example of ways in which the mechanizedsystem may be configured. Various modifications may be made to thatembodiment without departing from the scope of the invention.

A few such modifications will next be described, but many others arepossible and within the scope of the invention.

While the drawings show the two finger drivers in the housing 210 andeach roll driver 216 in a separate housing, other embodiments usedifferent layouts. For example, the design may be modified to positionthe roll drivers 216 in a common housing with the finger drivers. As asecond example, the roll drivers 216 might both be mounted in a commonhousing that is separate from the housing 210 containing the fingerdrivers. In another embodiment, the roll driver and finger driverassociated with the left-instrument may be a common housing, with aseparate housing used for both the roll driver and finger driverassociated with the right-instrument. Other embodiments might packageeach of the roll drivers and finger drivers as four separate components.

In other embodiments, the motors are integrated into the assemblies ofthe corresponding finger drivers and the roll drivers rather than beingdetachable from them.

Second Embodiment

The system 2A of the second embodiment, shown in FIG. 19, differs fromthe first embodiment primarily in that the features of the roll driverare incorporated into the base. More particularly, a base 218 a includesan elevated portion 216 a that houses the roll drive tube 248 (notshown). An instrument passage extends between a proximal opening 264 aand a distal opening (not shown) in the elevated portion 216 a. Theinstrument shaft extends through the passage elevated portion 216 abetween the command interface 250 and the finger drive assembly 200. Asterile tubular insert (not shown) is insertable through the instrumentpassage in the elevated portion 216 a to prevent the instrument 100 fromcontaminating the passage.

Third Embodiment

Referring to FIG. 20, a third embodiment of a surgical access system 2Bincludes a body 210 a and an insertion cannula 212 extending distallyfrom the body 210 a. Fingers 214 extend from the insertion cannula 212.The finger 214 may have properties similar to those described elsewherein this application.

Each finger includes a dedicated deployment mechanism operable toindependently reposition the distal portion of the fingers 214 toincrease or decrease its lateral separation from the longitudinal axisof the insertion cannula 212. Each deployment mechanism includes arigid, longitudinally slidable, member 14 a and at least one link arm 12a (two are shown for each finger). The rigid member 14 a may beconstructed of a proximal portion comprising a straight, single-lumen,tube made of stainless steel or rigid polymeric material, and a distalbar extending from the tubular proximal portion. The distal bar may beintegral with a portion of the wall of the tubular proximal portion.Each finger 214 extends distally from the lumen of the tubular proximalportion of the rigid member 14 a.

The deployment system works similarly to that described for the firstembodiment. Each link 12 a has a first end pivotally coupled to therigid member 118 and a second end pivotally coupled to a correspondingfinger 214, proximally of its distal end. In the illustrated embodiment,these pivotal connections are formed at collars 122 disposed on thefingers. The rigid member 14 a is longitudinally moveable relative tothe insertion cannula 212 to pivot the links 120 inwardly and outwardly.In the illustrated configuration, sliding 14 a in a distal directionpivots the second ends of the links 120 outwardly to deploy thecorresponding finger or to further separate the finger from thelongitudinal axis of the insertion cannula 212. Alternate configurationsmay operate in reverse, so that retraction of the member 14 a increasesthe separation of the fingers.

Each finger may further include a support member or strut 124 having afirst end pivotally connected to the collar 122 and a second endpivotally connected to the corresponding one of the members 14 a or tothe insertion cannula 212. The support struts 124 support the fingers,helping to maintain the longitudinal orientation of the fingers, andpreventing them from sagging or buckling during use.

Slide rings 126 are shown for independently sliding each member 14 alongitudinally for finger deployment, allowing the user toadvance/retract the member 14 a by advancing/retracting the ring 126relative to the body 210 a. The ring may include a ratchet featurefunction as described in the '307 application, which releasably locksthe finger in a chosen longitudinal and lateral position by releasablyengaging the longitudinal position of the member 14 a. FIG. 20 showsthat this arrangement allows each finger to be deployed to have adifferent amount of lateral separation and longitudinal extension.

The tips T of instruments 100 are shown extending from the distal endsof the fingers. The body 210 a includes proximal openings 128 forreceiving the instruments. To deploy an instrument 100 from a finger214, the tip of that instrument is inserted through one of the proximalopenings 128 and advanced through the body 210 a, insertion cannula 212and finger until its tip T or end effector extends out of the finger. Inthe FIG. 20 drawing, the handle 104 for the instrument used through thefinger on the left is not shown, so as to allow the proximal opening 128to be seen.

A primary difference between the third and first embodiments is that thefeatures described for inclusion in the first embodiment's fingerdrivers, roll drivers, command interface (including the instrument box)and base unit are incorporated into the housing 210 a.

Sensors 130 are positioned on the body 210 a to sense pitch and yawmovement of the instrument handle 104. Motors 236 a, b in the body 210 aare engaged with cables that extend through the fingers and that areanchored to the fingers (e.g. at 90 degree intervals) to deflect thefingers according to the sensed position of the handle. For example, afirst motor 236 a may be positioned to drive a first pair of cablescorresponding to yaw motion of the finger distal end, and a second motor236 b may be positioned to drive a second pair of cables correspondingto pitch motion of the finger distal end.

Automation may also be provided for driving axial rotation of aninstrument disposed through a finger. A handle sensor 304 is positionedto sense axial rotation of the instrument handle 104, and is operativelyassociated with a roll motor 238 that will produce or aid an axial rollof the instrument or a finger using gear 134.

As with the first embodiment, actuation of the instrument's endeffector, such as the opening/closing of jaws, is carried out inconventional fashion using actuators (e.g. levers, knobs, triggers,slides, etc.) on the instrument handle. If desired, an instrument may bewithdrawn from the system during the procedure, and replaced with adifferent instrument, which again may be steered and axially rotatedthrough manipulation of the handle as described.

The system 100 may include a mount 90 engageable with a stabilizationarm such as the arm 204 (FIG. 1B) that can be coupled to a cart, thesurgical table or to another fixture within the operating room. Thestabilization arm may be manually positionable or adjustable using motordriven joints and telescoping members, allowing the height andorientation of the system 2B to be adjusted using a user input such asfoot pedals or other input devices.

Fourth Embodiment

The FIG. 21 embodiment is similar to the FIG. 20 embodiment, but furtherincorporates a mechanism for Z-axis movement of each finger 214. Whileuse of the slide ring 126 in the FIG. 20 embodiment produces a z-axischange of the corresponding finger position, the FIG. 21 arrangementallows for z-axis movement that is independent of the lateral positionof the finger relative to the insertion cannula 212.

In particular, the system has two body sections 210 c, each of which islongitudinally slidable along a central track 136. Each body section iscoupled to one of the fingers and its corresponding deployment system(member 14 a, links 12 a, support strut 124, deployment ring 126). Inone embodiment, the insertion cannula 212 is coupled to the track 136,and each finger and its drive and deployment systems move longitudinallyrelative to the cannula in response to manual pushing/pulling by theuser. While the primary z-axis adjustment is now carried through on aplatform with a linear bearing for each side of the system, thedeployment mechanism remains for the adjustment of the tool separation(identified as x-axis in the drawings). Note that each side has anindependent deployment system so that the span is independentlycontrolled for each instrument.

Fifth Embodiment

The FIG. 22 embodiment is similar to the FIG. 21 embodiment, but isprovided in a more modular format. This embodiment includes independentbody sections 210 d which house the pitch, yaw and roll motors 236 a, b,230, the sensors 130, 304, and which include the opening 128 forreceiving the instrument 100. A pair of finger/roll driver 203 a eachhaving pulleys 232, cables (not shown), and a roll drive tube 248 areprovided, with each finger/roll driver 203 a connected to one of thefingers 214. Each finger/roll driver 203 a is releasably engagable witha body section 210 d in a manner that allows the motors in the bodysection 210 d module to actuate the pulleys 232 in finger/roll driver203 a so as to tension the cables and roll the finger/roll driver 203 ato steer the finger and roll the instrument. Slide rings 126 for fingerseparation (x-axis) are located on the finger/roll drivers 203 a.

Sixth Embodiment

In the FIG. 20-22 embodiments, pitch, roll and yaw are sensed and thefinger is electromechanically controlled to position the instrument,however the jaw clamping action or other end effector action of theinstrument is mechanically driven by a mechanical actuator on theinstrument handle. The FIG. 23 embodiment is largely similar to the FIG.22 embodiment, but rather than using a hand instrument having amechanical actuator, it uses an alternate surgical instrument 100 a. Theinstrument 100 a engages with a motor 138 in the motor module that isactivated to operate the end effector (e.g. jaw) of the tool. In oneembodiment, control of the finger and roll drivers is responsive to usermanipulation of the instrument 103 a to control pitch, roll and yaw asdiscussed with respect to prior embodiments, but the system isinstrument configured to receive signals from an input device (e.g. aswitch, foot pedal) to initiate actuation of the end effector via motor138. In other embodiments, the pitch, roll, yaw and jaw motors may beoperable in response to signals received from a separate user inputdevice such as a joystick or other forms of input device(s) rather thanmanual manipulation of the instrument 103 a.

Seventh Embodiment

The FIG. 24 embodiment is similar to the FIG. 23 embodiment, but itautomates the z-axis movement using a motor 140 that advances/retractsthe bodies 210 e and the finger/roll driver 203 a along the track 136.Moreover, it eliminates the mechanical deployment mechanism and insteadautomates the x-axis or lateral positioning of the finger using anadditional motor 142 in each body 210 e. The motor 142 advances/retractsthe element 14 a to expand the links 12 a for deployment and x-axispositioning.

Automating the z- and x-axis movement allows for complex volumetricmotions of the instrument beyond what can be achieved using mechanicalz- and x-axis movement. Providing a dynamic z-axis increases reach ofthe instrument while introducing a dynamic x-axis enables complexorientation movements of the instrument tips. Tip movement in thex-direction can in a sense be de-coupled from movement in thez-direction, by automatically adjusting the finger's z-axis position tooff-set z-axis changes resulting from pivoting of the links 12 a duringx-axis adjustments.

FIG. 25 shows but one example of a user input device that can be used insystems such as the FIGS. 23 and 24 systems that use input devices thatare separate from the instrument handle and shaft. A input device 500shown in FIG. 25 includes a handle to be manipulated by a user inaccordance with the desired position of the surgical instrument. Theinput device incorporates at least four sensors (associated withmultiple pivot joints in a control handle) and an actuator 502 forsimulating the grasping load to be achieved at the instrument's endeffector. The input device is connected to the body 210 d, 210 e throughdigital communication wires and can be located on or near the body 210d, 210 e at the patient's bedside, preferably within the sterile field.For example, the input device 500 and the body might be positioned on acommon arm (such as arm 204), on different arms supported by a commoncart or other fixture (e.g. the operating table or a ceiling mount), oron separate arms on the same or different fixtures. The FIGS. 23 and 24systems may be provided with various interchangeable tools 100 a, eachhaving a different end effector, allowing the user to exchange toolmodules as needed during the course of a surgical procedure.

Eighth Embodiment

FIG. 26 shows a system 2E that is similar to the first embodiment.However, the finger drive assembly 203, roll drivers 216, commandinterfaces 250, motor drivers and associated electronics are integratedinto a single component. Two steering motors 236 a, b are shown on eachside of the system 2E, one for each pair of cables. However, each cablemay instead have its own dedicated motor.

While certain embodiments have been described above, it should beunderstood that these embodiments are presented by way of example, andnot limitation. It will be apparent to persons skilled in the relevantart that various changes in form and detail may be made therein withoutdeparting from the spirit and scope of the invention. This is especiallytrue in light of technology and terms within the relevant art(s) thatmay be later developed. Moreover, features of the various disclosedembodiments may be combined in various ways to produce variousadditional embodiments.

Any and all patents, patent applications and printed publicationsreferred to above, including for purposes of priority, are incorporatedherein by reference.

1. A surgical system, comprising: an instrument driver having a distalend positionable in a body cavity; a user input device, wherein theinstrument driver and user input device are positioned to removablyreceive distal and proximal portions, respectively, of a surgicalinstrument, the user input device configured to generate movementsignals in response to manual manipulation of the proximal portion ofthe surgical instrument; and at least one motor operably coupled to theinstrument driver, the motor operable to actuate the instrument driverin response to the movement signals and to thereby change position ofthe distal portion of the surgical instrument within the body cavity. 2.The system of claim 1, wherein: the instrument driver comprises asteerable finger having a lumen proportioned to receive a distal portionof a surgical instrument, at least one actuation element extends atleast partially through the finger; and the motor is operable inresponse to the movement signals to cause tensioning of the actuationelement so as to deflect the finger.
 3. The system of claim 2, wherein:the input device includes a base and an instrument receiver on the base,the instrument receiver manually moveable relative to the base in atleast two degrees of freedom to generate the movement signals; said atleast one actuation element comprises a plurality of actuation elements;said motor comprises at least two motors operable in response to themovement signals to deflect the finger in at least two degrees offreedom.
 4. The system of claim 2, further including: a roll driverpositioned to rotationally couple with a surgical instrument received bythe instrument driver and the input device; a roll input deviceconfigured to generate roll signals in response to manual manipulationof at least one of a moveable member on the roll input device and aproximal portion of the surgical instrument; and a roll motor operablycoupled to the roll driver, the roll motor operable to move the rolldriver in response to the roll movement signals, such that said rolldriver axially rotates the distal portion of the surgical instrument. 5.The system of claim 4, wherein the roll input device is configured togenerate the roll signals in response to manual axial rotation of asurgical instrument positioned in contact with the roll input device. 6.The system of claim 4 wherein the roll input device is configured togenerate the roll signals in response to manual rotation of a knob onthe roll input device.
 7. The system of claim 4 wherein the roll driveris configured to permit longitudinal movement of a surgical instrumentrelative to the roll driver when the surgical instrument is rotationallycoupled with the roll driver.
 8. The system of claim 7, furtherincluding a sensor positioned to generate signals in response to achange in a longitudinal position of a surgical instrument.
 9. Thesystem of claim 4, wherein: the roll driver comprises a roll drivemember having an opening proportioned to receive a portion of a surgicalinstrument and features surrounding the opening lumen that arerotationally coupleable with the surgical instrument shaft; and the rollmotor is operable to axially rotate the roll drive member.
 10. Thesystem of claim 2, further including: an insertion support insertablethrough an incision into a body cavity; a second steerable finger, thefirst and second steerable fingers extending from a distal end of theinsertion support, the second steerable finger having a lumenproportioned to receive a distal portion of a second surgicalinstrument; a second user input device, wherein the second finger andsecond user input device are positioned to removably receive distal andproximal portions, respectively, of a second surgical instrument, thesecond user input device configured to generate second movement signalsin response to manual manipulation of the proximal portion of the secondsurgical instrument; and at least one second motor operably coupled tothe second finger, the second motor operable to deflect the secondfinger in response to the second movement signals.
 11. The system ofclaim 10, wherein at least one of the first and second fingers islaterally moveable from a first position in which the distal portion ofsaid finger is spaced from a longitudinal axis of the insertion supportby a first distance, and a second position in which a distal portion ofsaid finger is spaced from a longitudinal axis of the insertion supportby a second distance, wherein the second distance is greater than thefirst distance. 12-13. (canceled)
 14. The system of claim 11, furtherincluding a sensor positioned to generate a signal in response tomovement of at least one of the fingers between the first and secondpositions.
 15. The system of claim 1, further including a sensorpositioned to generate an instrument presence signal in response topositioning of a proximal portion of a surgical instrument on the inputdevice. 16-19. (canceled)
 20. The system of claim 4, wherein the rollinput device includes: a support, a receiver on the support, thereceiver having an opening for receiving a shaft of a surgicalinstrument, the receiver axially rotatable relative to the support; amagnet rotatable in response to axial rotation of the receiver; and aroll sensor positioned to detect rotation of the magnet and to generatethe roll movement signals in response to rotation of the magnet.
 21. Thesystem of claim 20, wherein the receiver is longitudinally moveablerelative to the support.
 22. The system of claim 20, wherein thereceiver is a tubular receiver having a lumen for receiving a shaft of asurgical instrument. 23-24. (canceled)
 25. The system of claim 4,wherein: the roll driver comprises a member having an openingproportioned to receive a distal shaft portion of a surgical instrument,the opening including first surface features positioned to rotationallycouple with second surface features of a shaft portion of a surgicalinstrument; and the roll motor is operable to axially rotate the member.26. The system of claim 25, wherein the member is a tubular memberhaving a lumen, the lumen having the surface features.
 27. The system ofclaim 26, wherein the first and second surface features are shaped topermit sliding longitudinal movement of the second surface featuresrelative to the first surface features while preventing rotationalmovement of the second surface features relative to the first surfacefeatures. 28-88. (canceled)
 89. The system of claim 27, wherein one ofthe first and second features includes at least one longitudinal splineand the other of the first and second features includes at least onelongitudinal groove, the spline slidably receivable within the groove.90. The system of claim 27, wherein said first feature comprises amember having an exterior surface defining a non-circular transversecross-section, wherein said second first feature comprises the lumenhaving a interior wall surface having non-circular transversecross-section.
 91. The system of claim 90, wherein each of the exteriorsurface of the member and the interior wall surface of the lumenincludes a plurality of longitudinally-extending planar surfaces. 92.The system of claim 27, wherein one of the first and second featuresincludes at least one pin and the other of the first and second featuresincludes at least one longitudinal groove, the pin longitudinallyslidable within the groove method includes causing said spline andgroove to rotationally engage.